Secagem de spirulina (Spirulina platensis) e utilização na produção de biscoitos.

Abstract

Microalgae have chemical and nutritional substances of relevance in human evolution, there is the Spirulinafor its high concentration of proteins and nutraceutical compounds. The research proposed to verify, between three drying methods, which one best preserves the nutritional properties of Spirulina. Between the convective drying, freeze drying and spray drying, was selected the dried biomass, with better chemical and nutritional properties and developed cookies added with Spirulina. For this study, quality control analyses were performed including physical, chemical, physico-chemical and microbiological parameters of the different forms of presentation of Spirulina, fresh and dry. In addition, a study was made of the best powders stored for 60 days in the temperatures of 30 and 40 °C determined according to the analysis mentioned above. Finally, it was developed cookies with different concentrations of Spirulina, which were subjected to analyses: physical, chemical, physico-chemical, microbiological and sensory. It was found in investigations that fresh Spirulinahas a high moisture content (86.79%) and water activity (0.985); low concentration of proteins(5.87%) and high value of ascorbic acid (60.67 mg/100 g). The best method adjusted to kinetics curves of convective drying at three different temperatures (40, 50 and 60 °C) was Midilli. The observation of images by scanning electron microscopy showedthat the biomass particles generated by drying methods in greenhouses and lyophilisation are not uniform when compared to the dried particles by spray drying. The model that best fit the experimental data of moisture adsorption isotherms to biomass, at 20, 30, and 40 °C, was Peleg. The isotherms were classified as type II and III. The physicochemical analyses with biomass showed that the method that best preserved the nutrients was by lyophilisation in view that presented the highest concentration of proteins, lipids, ascorbic acid, fiber and amino acids, and better results in the isotherms in the three mathematical models. Biomass obtained by this method was stored for 60 days and demonstrated stability for in terms of moisture content, a slight increase in water activity, reduction in brightness and yellowness, as well as increase in greenness. All microbiological analysis showed results that were within the existing national legislation. In the cookies, with the increase in the percentage of Spirulinain the formulation, there was an increased percentage of protein cookie, and mineral increase when compared to the biscuits produced only with the refined flour. Sensory analysis showed that the highest scores were attributed to the standard cookie with refined wheat flour. Standard cookie and cookie with 5% Spirulinawere preferred with the same intensity. It was conclude that the best drying method for conservation of Spirulina nutrients was lyophilisation. The characterization enrichment takes the biscuit added 15% Spirulinawhich the addition of 5% Spirulinacookie may be accepted by the public.